1. Field
The subject matter disclosed herein relates to electronic devices, and more particularly to methods, apparatuses and articles of manufacture for use by and/or in a mobile device to provide for positioning based, at least in part, on independently obtained barometric pressure measurements.
2. Information
As its name implies, a mobile device may be moved about, e.g. typically being carried by a user and/or possibly a machine. By way of some non-limiting examples, a mobile device may take the form of a cellular telephone, a smart phone, a tablet computer, a laptop computer, a wearable computer, a navigation and/or tracking device, etc.
Certain mobile devices may be enabled to receive location based services through the use of location determination technology including satellite positioning systems (SPS′), indoor location determination technologies and/or the like. In particular implementations, a mobile device may be provided with positioning assistance data to enable the mobile device to estimate its location using one or more positioning techniques or technologies.
In particular implementations of indoor navigation applications, it may be useful to determine an altitude of a mobile device. This may be particularly useful in navigating multi-level environments in which a mobile device may be provided with navigation assistance data such as locations of wireless signal transmitting devices, radio heatmaps, digital electronic maps, routing graphs, etc. As navigation assistance data for navigating an entire multi-level structure may be voluminous, a mobile device may only be provided with localized navigation assistance data depending, for example, on the general location of the mobile device (e.g., particular floor or wing of a building). In a particular implementation, a mobile device may be determined to be located on a particular level of a structure using one or more positioning techniques, and provided with navigation assistance data for use on that particular region.
In a particular implementation, a mobile device may resolve its location as being at particular level of a building by acquiring signals transmitted by transmitting devices positioned at known locations. For example, a mobile device may acquire a MAC address or other information modulating a signal transmitted by a transmitting device (e.g., IEEE std. 802.11 access point device, etc.) that is in range of the mobile device to infer that the mobile device is relatively close to the transmitting device located on a particular building floor. This technique, however, may be unreliable if a particular transmitting device transmits a wireless signal that may be acquired by a mobile device on different floors of the building.
In another particular implementation, mobile device may resolve its location as being a particular floor of a building by determining its altitude by comparing local barometric pressure measurements, e.g., obtained using on board barometric pressure sensor and/or the like, to a known reference barometric pressure corresponding to a reference altitude. However, such a reference barometric pressure is typically provided to the mobile device by some external source (e.g., a server) and typically has a limited period of relevance.